Field of the Invention
The present invention relates to a radiation-sensitive resin composition, a resist pattern-forming method, an acid generator and a compound.
Discussion of the Background
In radiation-sensitive resin compositions for use in microfabrication by lithography, an acid is generated at light-exposed sites upon irradiation with far ultraviolet rays such as an ArF excimer laser beam and a KrF excimer laser beam, charged particle rays such as electron beams, and the like, and chemical reactions catalyzed by the acid make the difference between the rates of dissolution at light-exposed sites and at light-unexposed sites of a resist film in a developer solution, thereby enabling a resist pattern to be formed on a substrate.
For such radiation-sensitive resin compositions, an improvement of resolving ability and rectangularity of a cross-sectional shape of a resist pattern has been demanded with the advance of microfabrication technologies. To address the demand, the type and/or the molecular structure of polymers, acid generating agents and other components for use in the composition have been investigated, and a combination thereof also further investigated in detail (see Japanese Unexamined Patent Application, Publication Nos. H11-125907, H8-146610 and 2000-298347).
In such a current situation in which miniaturization of resist patterns has been further in progress, not only superior rectangularity of a cross-sectional shape and superior resolving ability as described above, but also superior line width roughness (LWR) performances, in which LWR is indicative of variations of line widths in a resist pattern, are demanded. However, the aforementioned conventional radiation-sensitive resin compositions are incapable of meeting these demands.